Radio frequency (RF) communication channel reconfiguration in remote antenna unit (RAU) coverage areas in a distributed antenna system (DAS) to reduce RF interference

ABSTRACT

One embodiment of the disclosure relates to radio frequency (RF) communication channel reconfiguration in remote antenna unit (RAU) coverage areas in a distributed antenna system (DAS) to reduce RF interferences. In this regard, a spectrum optimization unit dynamically reconfigures RF communication channels employed by RAU coverage areas in a DAS to reduce or avoid adjacent-channel and/or co-channel RF interferences. Each of the RAU coverage areas provides a respective sniffed RF signal to the spectrum optimization unit. The spectrum optimization unit analyzes the respective sniffed RF signal to determine a respective lesser-interfered RF communication channel for an RAU coverage area and dynamically reconfigures the RAU coverage area to communicate on the respective lesser-interfered RF communication channel. By dynamically reconfiguring the RAU coverage areas to communicate on respective lesser-interfered RF communication channels, it is possible to reduce or avoid RF interferences to provide improved capacity, throughput, and coverage in the DAS.

PRIORITY APPLICATIONS

This is a continuation of International App. No. PCT/IL2016/050586,filed Jun. 7, 2016, which claims the benefit of priority under 35 U.S.C.§ 119 of U.S. Provisional Application No. 62/173,167 filed on Jun. 9,2015, the content of which is relied upon and incorporated herein byreference in its entirety.

BACKGROUND

The disclosure relates generally to distribution of communicationssignals in a distributed antenna system (DAS), and more particularly toradio frequency (RF) communication channel reconfiguration in remoteantenna unit (RAU) coverage areas to reduce RF interferences.

Wireless customers are increasingly demanding digital data services,such as streaming video signals. Some wireless customers use theirwireless devices in areas that are poorly serviced by conventionalcellular networks, such as inside certain buildings or areas where thereis less cellular coverage. One response to the intersection of these twoconcerns has been the use of DASs. The DASs can be particularly usefulwhen deployed inside buildings or other indoor environments where clientdevices may not otherwise be able to effectively receive RF signals froma source. The DASs are configured to provide multiple coverage areasinside the buildings to support higher capacity and better RF coverage.Each coverage area includes one or more RAUs configured to receive andtransmit communications signals to the client devices within antennarange of the RAU(s).

The RAUs located in the multiple DAS coverage areas may be configured toprovide a variety of wireless services, such as wideband code divisionmultiple access (WCDMA), long term evolution (LTE), and wireless localarea network (WLAN) and Wireless Fidelity (Wi-Fi) communicationsservices, as examples. In some cases, the RF signals associated with thevariety of wireless services may be transmitted and/or received onadjacent or overlapping RF channels. This can cause adjacent-channel orco-channel RF interferences between the RAUs located in the multiple DAScoverage areas. For example, the adjacent-channel RF interferences canoccur between one RAU configured to provide WLAN services on channel one(1) of a 2.4 GigaHertz (GHz) band (2.402 GHz-2.422 GHz) and another RAUconfigured to provide LTE services on an LTE band (2.3 GHz-2.4 GHz). Forexample, maximum transmission powers of LTE RF signals and WLAN signalsmay be 60 decibel-millwatts (dBm) and 30 dBm, respectively. As a result,capacity, throughput, and coverage of the WLAN services can be severelydegraded by the higher-powered LTE RF signals.

It may be possible to map out all RF bands and/or channels among themultiple DAS coverage areas during initial deployment of the DASs toavoid the adjacent-channel and the co-channel RF interferences in theDAS. However, it is difficult to anticipate every communications serviceand every RF spectrum distributed by the DAS during the initialdeployment, since new communications services, new RF spectrums, newcoverage areas, and/or new RAUs may be added to the DAS at a later time.

No admission is made that any reference cited herein constitutes priorart. Applicant expressly reserves the right to challenge the accuracyand pertinency of any cited documents.

SUMMARY

One embodiment of the disclosure relates to radio frequency (RF)communication channel reconfiguration in remote antenna unit (RAU)coverage areas in a distributed antenna system (DAS) to reduce RFinterferences. In DASs disclosed herein, a plurality of RAU coverageareas is provided in the DAS. Each RAU coverage area can be configuredto provide wireless communications services on a set of RF bands.However, the set of RF bands may be susceptible to RF performancedegradations resulting from RF interferences produced by RF transmitters(e.g., a cellular base station) located outside the RAU coverage area.In this regard, to reduce the RF interferences in the RAU coverage area,a spectrum optimization unit is provided. The spectrum optimization unitcan be provided in a head-end equipment (HEE) of the DAS as an example.The spectrum optimization unit is configured to dynamically reconfigureRF communication channels employed by RAUs in the RAU coverage area toreduce or avoid adjacent-channel and/or co-channel RF interferences. Atleast one of the RAUs in the RAU coverage area is configured to sniff RFsignals, which may include the RF interferences produced by the RFtransmitters located outside the RAU coverage area, and provide thesniffed RF signals to the spectrum optimization unit. The spectrumoptimization unit analyzes the sniffed RF signals to determine alesser-interfered RF communication channel for the RAUs in the RAUcoverage area. The spectrum optimization unit is further configured todynamically reconfigure the RAUs in the RAU coverage area to communicateon the lesser-interfered RF communication channel. By dynamicallydetermining and reconfiguring the RAUs in the RAU coverage area tocommunicate on the lesser-interfered RF communication channel, it ispossible to reduce or avoid the adjacent-channel and the co-channel RFinterferences to provide improved capacity, throughput, and coverage inthe RAU coverage area.

One embodiment of the disclosure relates to a spectrum optimization unitin a DAS. The spectrum optimization unit comprises a spectrum analysisunit communicatively coupled to a plurality of RAU coverage areas in aDAS, the plurality of RAU coverage areas each configured to communicateon a respective first RF channel. The spectrum analysis unit isconfigured to receive a plurality of sniffed RF signals from theplurality of RAU coverage areas, respectively, wherein each of theplurality of sniffed RF signals comprises one or more RF signals sniffedby at least one RAU in a respective RAU coverage area. For each of theplurality of sniffed RF signals, the spectrum analysis unit isconfigured to analyze the one or more RF signals comprised in thesniffed RF signals. For each of the plurality of sniffed RF signals, thespectrum analysis unit is also configured to determine a respectivesecond RF channel for the respective RAU coverage area if the respectivesecond RF channel is lesser-interfered than the respective first RFchannel. The spectrum optimization unit also comprises a controllerconfigured to reconfigure one or more RAU coverage areas among theplurality of RAU coverage areas to communicate on one or more respectivesecond RF channels in response to the one or more respective second RFchannels being determined by the spectrum analysis unit.

Another embodiment of the disclosure relates to a method for reducing RFinterferences in a plurality of RAU coverage areas in a DAS. The methodcomprises receiving a plurality of sniffed RF signals from a pluralityof RAU coverage areas, respectively. Each of the plurality of RAUcoverage areas is configured to communicate on a respective first RFchannel. For each of the plurality of sniffed RF signals received fromthe plurality of RAU coverage areas, the method also comprises analyzingthe plurality of sniffed RF signals to determine a respective second RFchannel for a respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel of therespective RAU coverage area. For each of the plurality of sniffed RFsignals received from the plurality of RAU coverage areas, the methodalso comprises reconfiguring the respective RAU coverage area tocommunicate on the respective second RF channel.

Another embodiment of the disclosure relates to a DAS. The DAS comprisesa plurality of RAU coverage areas in a DAS. Each of the plurality of RAUcoverage areas is configured to communicate on a respective first RFchannel. The DAS also comprises an HEE coupled to the plurality of RAUcoverage areas over a plurality of communications mediums, respectively.The HEE comprises a spectrum optimization unit. The spectrumoptimization unit comprises a spectrum analysis unit. The spectrumanalysis unit is configured to receive a plurality of sniffed RF signalsfrom the plurality of RAU coverage areas, respectively. Each of theplurality of sniffed RF signals comprises one or more RF signals sniffedby at least one RAU in a respective RAU coverage area. For each of theplurality of sniffed RF signals, the spectrum analysis unit isconfigured to analyze the one or more RF signals comprised in theplurality of sniffed RF signals. For each of the plurality of sniffed RFsignals, the spectrum analysis unit is also configured to determine arespective second RF channel for the respective RAU coverage area if therespective second RF channel is lesser-interfered than the respectivefirst RF channel. The spectrum optimization unit also comprises acontroller configured to reconfigure one or more RAU coverage areasamong the plurality of RAU coverage areas to communicate on one or morerespective second RF channels in response to the one or more respectivesecond RF channels being determined by the spectrum analysis unit.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from the description or recognized by practicing theembodiments as described in the written description and claims hereof,as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understand the natureand character of the claims.

The accompanying drawings are included to provide a furtherunderstanding, and are incorporated in and constitute a part of thisspecification. The drawings illustrate one or more embodiments and,together with the description, serve to explain principles and operationof the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary distributed antenna system(DAS);

FIG. 2A is an exemplary illustration of adjacent-channel and co-channelRF interferences that may occur among remote antenna unit (RAU) coverageareas in the DAS of FIG. 1;

FIG. 2B is an exemplary illustration of an over-sized RAU coverage areawith an expanded coverage boundary that is larger than a plannedcoverage boundary;

FIG. 3 is a schematic diagram of an exemplary DAS, wherein a head-endequipment (HEE) comprises a spectrum optimization unit configured todetect and reduce the adjacent-channel and the co-channel RFinterferences among a plurality of RAU coverage areas;

FIG. 4 is a flowchart illustrating an exemplary spectrum optimizationprocess that can be performed by the spectrum optimization unit of FIG.3 for detecting and reducing the adjacent-channel and the co-channel RFinterferences in the DAS;

FIG. 5 is a schematic diagram of an exemplary spectrum optimization unitconfigured to detect and reduce the adjacent-channel and the co-channelRF interferences in the DAS of FIG. 3 using a spectrum analysis unit, acontroller, and a signal interface;

FIG. 6 is a schematic diagram of an exemplary HEE for a DAS comprisingthe spectrum optimization unit of FIG. 5 and configured to detect andreduce the adjacent-channel and the co-channel RF interferences in anoptical fiber-based DAS;

FIG. 7 is a partial schematic cut-away diagram of an exemplary buildinginfrastructure in which an interference signal offset circuit, includingthe spectrum optimization unit of FIGS. 5 and 6, can be employed; and

FIG. 8 is a schematic diagram of a generalized representation of anexemplary controller that can be included in the spectrum optimizationunit of FIGS. 5 and 6 for detecting and reducing the adjacent-channeland the co-channel RF interferences in the DAS of FIG. 3, wherein anexemplary computer system is adapted to execute instructions from anexemplary computer-readable medium.

DETAILED DESCRIPTION

One embodiment of the disclosure relates to radio frequency (RF)communication channel reconfiguration in remote antenna unit (RAU)coverage areas in a distributed antenna system (DAS) to reduce RFinterferences. In DASs disclosed herein, a plurality of RAU coverageareas is provided in the DAS. Each RAU coverage area can be configuredto provide wireless communications services on a set of RF bands.However, the set of RF bands may be susceptible to RF performancedegradations resulting from RF interferences produced by RF transmitters(e.g., a cellular base station) located outside the RAU coverage area.In this regard, to reduce the RF interferences in the RAU coverage area,a spectrum optimization unit is provided. The spectrum optimization unitcan be provided in a head-end equipment (HEE) of the DAS as an example.The spectrum optimization unit is configured to dynamically reconfigureRF communication channels employed by RAUs in the RAU coverage area toreduce or avoid adjacent-channel and/or co-channel RF interferences. Atleast one of the RAUs in the RAU coverage area is configured to sniff RFsignals, which may include the RF interferences produced by the RFtransmitters located outside the RAU coverage area, and provide thesniffed RF signals to the spectrum optimization unit. The spectrumoptimization unit analyzes the sniffed RF signals to determine alesser-interfered RF communication channel for the RAUs in the RAUcoverage area. The spectrum optimization unit is further configured todynamically reconfigure the RAUs in the RAU coverage area to communicateon the lesser-interfered RF communication channel. By dynamicallydetermining and reconfiguring the RAUs in the RAU coverage area tocommunicate on the lesser-interfered RF communication channels, it ispossible to reduce or avoid the adjacent-channel and the co-channel RFinterferences to provide improved capacity, throughput, and coverage inthe RAU coverage area.

Before discussing examples of RF communication channel reconfigurationin RAU coverage areas in a DAS to reduce RF interferences starting atFIG. 3, discussion of an exemplary DAS that employs a communicationsmedium to support wireless communications services to a plurality ofRAUs as well as RF interference scenarios between the plurality of RAUsare first provided with references to FIGS. 1, 2A, and 2B. Thediscussion of specific exemplary aspects of RF communication channelreconfiguration in the RAU coverage areas in the DAS to reduce the RFinterferences starts later with reference to FIG. 3.

In this regard, FIG. 1 illustrates a distribution of communicationsservices to RAU coverage areas 10(1)-10(N) of a DAS 12, wherein ‘N’ isthe number of RAU coverage areas. These communications services caninclude cellular services such as long-term evolution (LTE), wirelessservices such as Wireless Fidelity (Wi-Fi) and BLUETOOTH™, andcombinations thereof, as examples. The RAU coverage areas 10(1)-10(N)may be remotely located. Each of the RAU coverage areas 10(1)-10(N) iscreated by and centered on one or more RAUs 14(1-M) connected to an HEE16 (e.g., a head-end controller or head-end unit or central unit),wherein M may represent different finite positive integers in the RAUcoverage areas 10(1)-10(N). Each of the RAU coverage areas 10(1)-10(N)corresponds to a planned coverage boundary BPLAN. The HEE 16 may becommunicatively coupled to a signal source 18, for example, a basetransceiver station (BTS) or a baseband unit (BBU). In this regard, theHEE 16 receives downlink communications signals 20D, which may comprisedownlink communications signals from a variety of communicationsservices, from the signal source 18 to be distributed to the one or moreRAUs 14(1-M) in each of the RAU coverage areas 10(1)-10(N). Each of theone or more RAUs 14(1-M) is configured to receive the downlinkcommunications signals 20D from the HEE 16 over a communications medium22 to be distributed to the respective RAU coverage areas 10(1)-10(N) ofthe one or more RAUs 14(1-M). In a non-limiting example, thecommunications medium 22 may be a wired communications medium, awireless communications medium, or an optical fiber-based communicationsmedium. Each of the one or more RAUs 14(1-M) in each of the RAU coverageareas 10(1)-10(N) may include an RF transmitter/receiver (not shown) anda respective antenna 24(1-M) operably connected to the RFtransmitter/receiver to wirelessly distribute the communicationsservices to client devices 26 within the respective RAU coverage areas10(1)-10(N). The one or more RAUs 14(1-M) are also configured to receiveuplink communications signals 20U, which may comprise uplinkcommunications signals corresponding to the variety of communicationsservices, from the client devices 26 within the respective RAU coverageareas 10(1)-10(N) to be distributed to the signal source 18. The size ofeach of the RAU coverage areas 10(1)-10(N) is determined by amount of RFpower transmitted by the one or more respective RAUs 14(1-M), receiversensitivity, antenna gain, and RF environment, as well as by RFtransmitter/receiver sensitivity of the client devices 26. The clientdevices 26 usually have a fixed maximum RF receiver sensitivity so thatthe above-mentioned properties of the one or more RAUs 14(1-M) mainlydetermine the size of each of the respective RAU coverage areas10(1)-10(N).

With continuing reference to FIG. 1, the downlink communications signals20D and the uplink communications signals 20U may be distributed by theRAU coverage areas 10(1)-10(N) on adjacent or overlapping downlink anduplink RF communication channels (not shown). As a result,adjacent-channel or co-channel RF interference can occur among the RAUcoverage areas 10(1)-10(N). In this regard, FIG. 2A is an exemplaryillustration of the adjacent-channel and the co-channel RF interferencesthat may occur in the RAU coverage areas 10(1)-10(N) of FIG. 1. Commonelements between FIGS. 1 and 2A are shown therein with common elementnumbers and will not be re-described herein.

With reference to FIG. 2A, in RAU coverage area 10(1) for example, RAU14(1) transmits a downlink communications signal 20D′ to a client device28(1) on Wi-Fi channel one (1) that ranges from 2.402 Gigahertz (GHz) to2.422 GHz (not shown). The RAU 14(1) in RAU coverage area 10(3) is alsotransmitting a downlink communications signal 20D″ to a client device28(2) on the Wi-Fi channel 1. The RAU 14(1) in the RAU coverage area10(3) may be transmitting the downlink communications signal 20D″ at ahigher power, which causes the downlink communications signal 20D″ toleak into the RAU coverage area 10(1). As a result, an RF receiver (notshown) of the client device 28(1) may be blocked by the leaked downlinkcommunications signal 20D″ and unable to receive the downlinkcommunications signal 20D′ correctly.

With continuing reference to FIG. 2A, in a non-limiting example, a BTS30, which may be located inside or outside the RAU coverage area 10(3),transmits a downlink communications signal 32 on LTE band forty (40)that ranges from 2.3 GHz to 2.4 GHz. In this regard, there are only two(2) Megahertz (MHz) of RF separation between the upper boundary (i.e.,2.4 GHz) of the LTE band 40 and the lower boundary (i.e., 2.402 GHz) ofthe Wi-Fi channel 1. Because the BTS 30 is configured to transmit thedownlink communications signal 32 at a higher RF power, an RF receiver(not shown) of the client device 28(2) may lose receiving sensitivityand be unable to receive the downlink communications signal 20D″ fromthe RAU 14(1) in the RAU coverage area 10(3) correctly.

With reference back to FIG. 1, when the DAS 12 is deployed, each of theRAU coverage areas 10(1)-10(N) is configured with the planned coverageboundary BPLAN to provide a planned capacity. In a non-limiting example,the planned capacity may be determined based on software simulations.However, the one or more RAUs 14(1-M) in one of the RAU coverage areas10(1)-10(N), for example, RAU coverage area 10(2), may be transmittingat a higher RF power. As a result, the RAU coverage area 10(2), forexample, may become an over-sized RAU coverage area and thus reducingthe planned capacity of the RAU coverage area 10(2). In this regard,FIG. 2B is an exemplary illustration of an over-sized RAU coverage area10′(2) with an expanded coverage boundary B_(ACTUAL) that is larger thanthe planned coverage boundary BPLAN. Common elements between FIGS. 1 and2B are shown therein with common element numbers and will not bere-described herein.

As shown in FIG. 2B, the expanded coverage boundary B_(ACTUAL) of theRAU coverage area 10(2) is larger than the planned coverage boundaryBPLAN because the one or more RAUs 14(1-M) may be transmitting at ahigher power level. As a result of the expanded coverage boundaryB_(ACTUAL), the planned capacity of the RAU coverage area 10(2) may bereduced.

The adjacent-channel and the co-channel RF interference scenariosdiscussed above in reference to FIG. 2A can have severe impact oncapacities, throughputs, and coverage ranges of the RAU coverage areas10(1)-10(N). Hence, it is desirable to dynamically detect and reduce theadjacent-channel and the co-channel RF interferences in the RAU coverageareas 10(1)-10(N). In this regard, as will be discussed in more detailbelow, FIG. 3 is a schematic diagram of an exemplary DAS 40, wherein anHEE 42 comprises a spectrum optimization unit 44 configured to detectand reduce the adjacent-channel and the co-channel RF interferences in aplurality of RAU coverage areas 46(1)-46(X).

With reference to FIG. 3, the HEE 42 is communicatively coupled to theplurality of RAU coverage areas 46(1)-46(X) by a plurality ofcommunications mediums 48(1)-48(X). In a non-limiting example, each ofthe plurality of communications mediums 48(1)-48(X) comprises arespective downlink data signal path 50DD and a respective uplink datasignal path 50UD. In another non-limiting example, the plurality ofcommunications mediums 48(1)-48(X) may be a plurality of opticalfiber-based communications mediums 48′(1)-48′(X). In anothernon-limiting example, in the plurality of optical fiber-basedcommunications mediums 48′(1)-48′(X), the respective downlink datasignal path 50DD is provided by a respective downlink data optical fiber(not shown) and the respective uplink data signal path 50UD is providedby a respective uplink data optical fiber (not shown).

With continuing reference to FIG. 3, the HEE 42 receives one or moredownlink communications signals 52(1)-52(Y) from one or morecommunications signal sources (not shown). The one or more downlinkcommunications signals 52(1)-52(Y) correspond to an RF channel set 53that may comprise multiple downlink RF channels (not shown). In otherwords, each of the one or more downlink communications signals52(1)-52(Y) determines a downlink RF channel to be used forcommunicating a respective downlink communications signal. The one ormore downlink communications signals 52(1)-52(Y) are provided to theplurality of RAU coverage areas 46(1)-46(X) over the respective downlinkdata signal path 50DD in the plurality of communications mediums48(1)-48(X). In this regard, each of the plurality of RAU coverage areas46(1)-46(X) is configured to operate on the downlink RF channeldetermined by the downlink communications signal being provided to therespective RAU coverage area. The HEE 42 also provides one or moreuplink communications signals 54(1)-54(Y) to the one or morecommunications signal sources, respectively. The one or more uplinkcommunications signals 54(1)-54(Y) are received from the plurality ofRAU coverage areas 46(1)-46(X) over the respective uplink data signalpath 50UD in the plurality of communications mediums 48(1)-48(X). Forconvenience of discussion and illustration, RAU coverage area 46(Z),which may be any of the plurality of RAU coverage areas 46(1)-46(X), isdiscussed hereinafter as a non-limiting example.

With continuing reference to FIG. 3, the RAU coverage area 46(Z)comprises a plurality of RAUs 56(1)-56(P). The RAU coverage area 46(Z)is configured to receive downlink communications signal 52(A) from theHEE 42 and provides uplink communications signal 54(A) to the HEE 42.Each of the plurality of RAUs 56(1)-56(P) is configured to communicatewith one or more client devices (not shown) on a first RF channel (notshown) determined by the downlink communications signal 52(A). Aspreviously shown in FIG. 2A, the RAU coverage area 46(Z) may experienceinterference from the downlink communications signal 20D″ and/or thedownlink communications signal 32. In this regard, at least one RAUamong the plurality of RAUs 56(1)-56(P) in the RAU coverage area 46(Z)is configured to generate a sniffed RF signal 58(Z). In a non-limitingexample, the sniffed RF signal 58(Z) may be a sniffed downlink RFsignal. In another non-limiting example, the sniffed RF signal 58(Z) maybe a sniffed uplink RF signal. In this regard, in the DAS 40, theplurality of RAU coverage areas 46(1)-46(X) may provide a plurality ofsniffed RF signals 58(1)-58(X) to the spectrum optimization unit 44,respectively. The sniffed RF signal 58(Z) may include one or moredownlink RF signals, including the downlink communications signal 20D″and/or the downlink communications signal 32, that are present in theRAU coverage area 46(Z) and can be sniffed by at least one RAU among theplurality of RAUs 56(1)-56(P). The sniffed RF signal 58(Z) may alsoinclude one or more uplink RF signals in the first RF channel. Thesniffed RF signal 58(Z) may also include one or more configured RFsignals (e.g., RF signals communicated by Wi-Fi access points) in thefirst RF channel. The sniffed RF signal 58(Z) may also include one ormore ad hoc RF signals (e.g., RF signals emitted by microwave oven) inthe first RF channel. In a non-limiting example, the sniffed RF signal58(Z) may be provided to the HEE 42 as an in-band control signal overthe respective uplink data signal path 50UD in communications medium48(Z).

With continuing reference to FIG. 3, the HEE 42 includes the spectrumoptimization unit 44 to detect and reduce the adjacent-channel and theco-channel RF interferences in the RAU coverage area 46(Z). In thisregard, the spectrum optimization unit 44 in the HEE 42 in this examplereceives and analyzes the sniffed RF signal 58(Z) provided by the RAUcoverage area 46(Z). By analyzing the sniffed RF signal 58(Z), thespectrum optimization unit 44 can determine whether there exists asecond RF channel (not shown) in the RF channel set 53 that islesser-interfered than the first RF channel used by the RAU coveragearea 46(Z). The spectrum optimization unit 44 may determine the secondRF channel that is lesser-interfered than the first RF channel based ona range of factors, including but not limited to signal-to-noise ratio(SNR), received-signal-strength indication (RSSI), bit error rate (BER),and strength of the sniffed RF signal 58(Z). The spectrum optimizationunit 44 may reference the range of factors individually or incombination to determine the second RF channel that is lesser-interferedthan the first RF channel. In one non-limiting example, the second RFchannel may be different from the first RF channel, indicating that thesecond RF channel is lesser-interfered than the first RF channel. Inanother non-limiting example, the second RF channel may be the same asthe first RF channel, indicating that the second RF channel does notexist. In this regard, if the second RF channel exists for the RAUcoverage area 46(Z), the spectrum optimization unit 44 can reconfigurethe RAU coverage area 46(Z) to communicate on the second RF channel,thus reducing the adjacent-channel and/or the co-channel interferencesin the RAU coverage area 46(Z). To do so, the spectrum optimization unit44 may reroute downlink communications signal 52(B), which is associatedwith the second RF channel as an example, to the RAU coverage area46(Z). In a non-limiting example, the spectrum optimization unit 44 maycontinue routing the downlink communications signal 52(A), which isassociated with the first RF channel, to the RAU coverage area 46(Z) orrerouting the downlink communications signal 52(A) to another RAUcoverage area among the plurality of RAU coverage areas 46(1)-46(X). Inanother non-limiting example, the spectrum optimization unit 44 mayreroute the downlink communications signal 52(A) and the downlinkcommunications signal 52(B) via a channel control signal 60. In anothernon-limiting example, the spectrum optimization unit 44 may also analyzethe sniffed RF signal 58(Z) to determine a downlink RF signal among theone or more downlink RF signals and the one or more uplink RF signalscomprised in the sniffed RF signal 58(Z) received from a cellular basestation (BS) or a mobile station (MS).

With continuing reference to FIG. 3, the spectrum optimization unit 44also analyzes the sniffed RF signal 58(Z) to detect a power-leaking RAUthat interferes with the RAU coverage area 46(Z) from another RAUcoverage area that is different from the RAU coverage area 46(Z). Ifthere exists the power-leaking RAU, the spectrum optimization unit 44can reduce RF power level of the power-leaking RAU, thus reducing theadjacent-channel or the co-channel interference caused by thepower-leaking RAU in the RAU coverage area 46(Z). In a non-limitingexample, the RF power level of the power-leaking RAU may be reducedmanually or via a power control signal (not shown) provided by thespectrum optimization unit 44.

Furthermore, by analyzing the sniffed RF signal 58(Z), the spectrumoptimization unit 44 is also able to determine whether the RAU coveragearea 46(Z) is an over-sized RAU coverage area with an expanded coverageboundary B_(ACTUAL), such as the over-sized RAU coverage area 10′(2) ofFIG. 2B. Accordingly, the spectrum optimization unit 44 can reduce RFpower levels of one or more RAUs among the plurality of RAUs 56(1)-56(P)in the RAU coverage area 46(Z) to reduce coverage boundary of the RAUcoverage area 46(Z), thus ensuring sufficient capacity in the RAUcoverage area 46(Z).

Hence, by dynamically reconfiguring the RAU coverage area 46(Z) tocommunicate on the second RF channel, it is possible to reduce or avoidthe adjacent-channel and the co-channel RF interferences in the RAUcoverage area 46(Z) to provide improved capacity, throughput, andcoverage in the RAU coverage area 46(Z). Accordingly, by reducing theadjacent-channel and the co-channel RF interferences in each of theplurality of RAU coverage areas 46(1)-46(X), it is possible to reduce oravoid the adjacent-channel and the co-channel RF interferences in theDAS 40.

FIG. 4 is a flowchart illustrating an exemplary spectrum optimizationprocess 70 that can be performed by the spectrum optimization unit 44 ofFIG. 3 for detecting and reducing the adjacent-channel and theco-channel RF interferences in the DAS 40. As shown in FIG. 4, thespectrum optimization unit 44 receives the plurality of sniffed RFsignals 58(1)-58(X) from the plurality of RAU coverage areas46(1)-46(X), respectively (block 72). Each of the plurality of RAUcoverage areas 46(1)-46(X) is configured to communicate on a respectivefirst RF channel that is determined by a downlink communications signalamong the one or more downlink communications signals 52(1)-52(Y). Thespectrum optimization unit 44 is configured to analyze each of theplurality of sniffed RF signals 58(1)-58(X) to determine a respectivesecond RF channel for a respective RAU coverage area providing thesniffed RF signal 58(Z) (block 74). If the respective second RF channelis lesser-interfered than the respective first RF channel of therespective RAU coverage area, the spectrum optimization unit 44reconfigures the respective RAU coverage area to communicate on therespective second RF channel (block 76).

In a non-limiting example, the spectrum optimization unit 44 may beprovided as a combination of circuitries and/or functional blocks. Toillustrate one exemplary embodiment of the spectrum optimization unit44, FIG. 5 is provided. In this regard, FIG. 5 is a schematic diagram ofan exemplary spectrum optimization unit 44(1) configured to detect andreduce the adjacent-channel and the co-channel RF interferences in theDAS 40 of FIG. 3 using a spectrum analysis unit 82, a controller 84, anda signal interface 86. Common elements between FIGS. 3 and 5 are showntherein with common element numbers and will not be re-described herein.

With reference to FIG. 5, the spectrum analysis unit 82 receives theplurality of sniffed RF signals 58(1)-58(X) from the plurality of RAUcoverage areas 46(1)-46(X) (not shown), respectively. In a non-limitingexample, the spectrum analysis unit 82 may receive the plurality ofsniffed RF signals 58(1)-58(X) either directly from the plurality of RAUcoverage areas 46(1)-46(X) or through an RF signal router 88 coupled tothe plurality of communications mediums 48(1)-48(X). Each of theplurality of RAU coverage areas 46(1)-46(X) is configured to communicateon the respective first RF channel. The spectrum analysis unit 82 isconfigured to analyze each of the plurality of sniffed RF signals58(1)-58(X) to determine whether there exists the respective second RFchannel (not shown) in the RF channel set 53 that is lesser-interferedthan the respective first RF channel of the respective RAU coverage areafrom which the sniffed RF signal is received. For some of the pluralityof RAU coverage areas 46(1)-46(X), the respective second RF channels maybe different from the respective first RF channels, indicating that therespective second RF channels are lesser-interfered than the respectivefirst RF channels. In this regard, one or more second RF channels may bedetermined for the one or more RAU coverage areas among the plurality ofRAU coverage areas 46(1)-46(X), respectively. In a non-limiting example,the spectrum analysis unit 82 then provides a spectrum analysis signal90 to the controller 84. The spectrum analysis signal 90 comprises theone or more second RF channels for the one or more RAU coverage areasamong the plurality of RAU coverage areas 46(1)-46(X).

With continuing reference to FIG. 5, in another non-limiting example,the controller 84 generates and provides the channel control signal 60to the signal interface 86 in response to receiving the spectrumanalysis signal 90. The signal interface 86 then reconfigures the one ormore RAU coverage areas among the plurality of RAU coverage areas46(1)-46(X) to communicate on the one or more second RF channels,respectively.

With continuing reference to FIG. 5, the spectrum analysis unit 82 alsoanalyzes the plurality of sniffed RF signals 58(1)-58(X) to detect thepower-leaking RAU in a RAU coverage area among the plurality of RAUcoverage areas 46(1)-46(X) that interferes with another RAU coveragearea among the plurality of RAU coverage areas 46(1)-46(X). If thepower-leaking RAU is detected, the controller 84 can reduce the RF powerlevel of the power-leaking RAU, thus reducing the adjacent-channel orthe co-channel interference caused by the power-leaking RAU. In anon-limiting example, the spectrum analysis unit 82 may notify thecontroller 84 about the power-leaking RAU via a power leakage signal 92.

Furthermore, by analyzing the plurality of sniffed RF signals58(1)-58(X), the spectrum analysis unit 82 is also able to determinewhether the RAU coverage area among the plurality of RAU coverage areas46(1)-46(X) is an over-sized RAU coverage area, such as the over-sizedRAU coverage area 10′(2) of FIG. 2B. Accordingly, the controller 84 canreduce the RF power levels of the over-sized RAU coverage area to reducethe coverage boundary of the over-sized RAU coverage area. Furthermore,it is also possible to determine whether the RAU coverage area among theplurality of RAU coverage areas 46(1)-46(X) is an under-sized RAUcoverage area. Accordingly, the controller 84 can increase the RF powerlevels of the under-sized RAU coverage area to increase the coverageboundary of the under-sized RAU coverage area.

With continuing reference to FIG. 5, the signal interface 86 alsoreceives the one or more downlink communications signals 52(1)-52(Y). Ina non-limiting example, the signal interface 86 may be configured toadapt the one or more downlink communications signals 52(1)-52(Y) into aplurality of downlink RF signals 94(1)-94(X) appropriate forcommunicating in the DAS 40 (not shown) of FIG. 3. In turn, the signalinterface 86 provides the plurality of downlink RF signals 94(1)-94(X)to the RF signal router 88 for communicating to the plurality of RAUcoverage areas 46(1)-46(X).

With continuing reference to FIG. 5, the RF signal router 88 is coupledto the plurality of RAU coverage areas 46(1)-46(X) over the plurality ofcommunications mediums 48(1)-48(X), respectively. The RF signal router88 provides the plurality of downlink RF signals 94(1)-94(X) to theplurality of RAU coverage areas 46(1)-46(X) over the respective downlinkdata signal paths 50DD (not shown) in the plurality of communicationsmediums 48(1)-48(X).

With continuing reference to FIG. 5, the RF signal router 88 receives aplurality of uplink RF signals 96(1)-96(X) from the plurality of RAUcoverage areas 46(1)-46(X) over the respective uplink data signal paths50UD (not shown) in the plurality of communications mediums 48(1)-48(X).The RF signal router 88 then provides the plurality of uplink RF signals96(1)-96(X) to the signal interface 86. In a non-limiting example, thesignal interface 86 adapts the plurality of uplink RF signals96(1)-96(X) into the one or more uplink communications signals54(1)-54(Y) that are appropriate to be provided to the one or morecommunications signals sources (not shown). The RF signal router 88 alsoreceives the plurality of sniffed RF signals 58(1)-58(X) from theplurality of RAU coverage areas 46(1)-46(X) over the plurality ofcommunications mediums 48(1)-48(X), respectively. The RF signal router88 is configured to provide the plurality of sniffed RF signals58(1)-58(X) to the spectrum analysis unit 82. In a non-limiting example,the RF signal router 88 may provide the plurality of sniffed RF signals58(1)-58(X) to the spectrum analysis unit 82 in response to receiving acontrol signal 98 from the controller 84. In another non-limitingexample, the RF signal router 88 may be configured receive a pluralityof combined uplink signals 100(1)-100(X) from the plurality of RAUcoverage areas 46(1)-46(X) over the respective uplink data signal paths50UD in the plurality of communications mediums 48(1)-48(X). In thisregard, the RF signal router 88 is configured to separate the pluralityof uplink RF signals 96(1)-96(X) and the plurality of sniffed RF signals58(1)-58(X) from the plurality of combined uplink signals 100(1)-100(X)before providing the plurality of uplink RF signals 96(1)-96(X) and theplurality of sniffed RF signals 58(1)-58(X) to the signal interface 86and the spectrum analysis unit 82, respectively.

As illustrated in FIG. 3, the plurality of communications mediums48(1)-48(X) may be provided as the plurality of optical fiber-basedcommunications mediums 48′(1)-48′(X). In this regard, FIG. 6 is aschematic diagram of an exemplary HEE 42(1) comprising the spectrumoptimization unit 44(1) of FIG. 5 and configured to detect and reducethe adjacent-channel and the co-channel RF interferences in an opticalfiber-based DAS 110. Common elements between FIGS. 5 and 6 are showntherein with common element numbers and will not be re-described herein.

With reference to FIG. 6, the HEE 42(1) comprises at least one opticalinterface module (OIM) 112. The OIM 112 is coupled to the plurality ofRAU coverage areas 46(1)-46(X) (not shown) over a plurality of downlinkoptical fiber-based communications mediums 114(1)-114(X) and a pluralityof uplink optical fiber-based communications mediums 116(1)-116(X),respectively. Each of the plurality of downlink optical fiber-basedcommunications mediums 114(1)-114(X) comprises a respective downlinkdata signal path 118DD. Each of the plurality of downlink opticalfiber-based communications mediums 114(1)-114(X) also comprises arespective uplink data signal path 118UD.

With continuing reference to FIG. 6, the OIM 112 receives and convertsthe plurality of downlink RF signals 94(1)-94(X) into a plurality ofdownlink optical signals 120(1)-120(X) for communicating to theplurality of RAU coverage areas 46(1)-46(X), respectively. The OIM 112receives a plurality of uplink optical signals 122(1)-122(X) and aplurality of optical sniffed RF signals 124(1)-124(X) from the pluralityof RAU coverage areas 46(1)-46(X), respectively. The OIM 112 convertsthe plurality of uplink optical signals 122(1)-122(X) into the pluralityof uplink RF signals 96(1)-96(X), respectively, and provides theplurality of uplink RF signals 96(1)-96(X) to the RF signal router 88.The OIM 112 converts the plurality of optical sniffed RF signals124(1)-124(X) into the plurality of sniffed RF signals 58(1)-58(X),respectively, and provides the plurality of sniffed RF signals58(1)-58(X) to the RF signal router 88.

The spectrum optimization unit 44(1) of FIGS. 5 and 6 may be provided inan indoor environment, as illustrated in FIG. 7. FIG. 7 is a partialschematic cut-away diagram of an exemplary building infrastructure 130in which the spectrum optimization unit 44(1) of FIGS. 5 and 6 can beemployed. The building infrastructure 130 in this embodiment includes afirst (ground) floor 132(1), a second floor 132(2), and a third floor132(3). The floors 132(1)-132(3) are serviced by a central unit 134 toprovide antenna coverage areas 136 in the building infrastructure 130.The central unit 134 is communicatively coupled to a base station 138 toreceive downlink communications signals 140D from the base station 138.The central unit 134 receives uplink communications signals 140U fromRAUs 142. The downlink communications signals 140D and uplinkcommunications signals 140U communicated between the central unit 134and the RAUs 142 are carried over a riser cable 144. The riser cable 144may be routed through interconnect units (ICUs) 146(1)-146(3) dedicatedto each of the floors 132(1)-132(3) that route the downlinkcommunications signals 140D and uplink communications signals 140U tothe RAUs 142 and also provide power to the RAUs 142 via array cables148.

FIG. 8 is a schematic diagram illustrating additional details of anexemplary computer system 150 that could be employed in the controllersdiscussed above, including, but not limited to, the controller 84 in thespectrum optimization unit 44(1) of FIGS. 5 and 6. As discussed above,the controller 84 is configured to detect and reduce theadjacent-channel and the co-channel RF interferences in the DAS 40 ofFIG. 3. In this regard, the computer system 150 is adapted to executeinstructions from an exemplary computer-readable medium to perform theseand/or any of the functions or processing described herein.

With reference to FIG. 8, the computer system 150 may include a set ofinstructions that may be executed to predict frequency interference toavoid or reduce interference in a multi-frequency DAS. The computersystem 150 may be connected (e.g., networked) to other machines in aLAN, an intranet, an extranet, or the Internet. While only a singledevice is illustrated, the term “device” shall also be taken to includeany collection of devices that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein. The computer system 150 may be a circuitor circuits included in an electronic board card, such as a printedcircuit board (PCB), a server, a personal computer, a desktop computer,a laptop computer, a personal digital assistant (PDA), a computing pad,a mobile device, or any other device, and may represent, for example, aserver or a user's computer.

The computer system 150 in this embodiment includes a processing circuit(“processor 152”), a main memory 154 (e.g., read-only memory (ROM),flash memory, dynamic random access memory (DRAM), such as synchronousDRAM (SDRAM), etc.), and a static memory 156 (e.g., flash memory, staticrandom access memory (SRAM), etc.), which may communicate with eachother via a data bus 158. Alternatively, the processor 152 may beconnected to the main memory 154 and/or the static memory 156 directlyor via some other connectivity bus or connection. The processor 152 maybe a controller like the controller 84 of FIGS. 5 and 6. The main memory154 and the static memory 156 may be any type of memory.

The processor 152 may be a microprocessor, central processing unit, orthe like. More particularly, the processor 152 may be a complexinstruction set computing (CISC) microprocessor, a reduced instructionset computing (RISC) microprocessor, a very long instruction word (VLIW)microprocessor, a processor implementing other instruction sets, orother processors implementing a combination of instruction sets. Theprocessor 152 is configured to execute processing logic in instructionsfor performing the operations and steps discussed herein.

The computer system 150 may further include a network interface device160. The computer system 150 also may or may not include an input 162,configured to receive input and selections to be communicated to thecomputer system 150 when executing instructions. The computer system 150also may or may not include an output 164, including, but not limitedto, a display, a video display unit (e.g., a liquid crystal display(LCD) or a cathode ray tube (CRT)), an alphanumeric input device (e.g.,a keyboard), and/or a cursor control device (e.g., a mouse).

The computer system 150 may or may not include a data storage devicethat includes instructions 166 stored in a computer-readable medium 168.The instructions 166 may also reside, completely or at least partially,within the main memory 154 and/or within the processor 152 duringexecution thereof by the computer system 150, the main memory 154 andthe processor 152 also constituting the computer-readable medium 168.The instructions 166 may further be transmitted or received over anetwork 170 via the network interface device 160.

While the computer-readable medium 168 is shown in an exemplaryembodiment to be a single medium, the term “computer-readable medium”should be taken to include a single medium or multiple mediums (e.g., acentralized or distributed database, and/or associated caches andservers) that store the one or more sets of instructions. The term“computer-readable medium” shall also be taken to include any mediumthat is capable of storing, encoding, or carrying a set of instructionsfor execution by the processing device and that cause the processingdevice to perform any one or more of the methodologies of theembodiments disclosed herein. The term “computer-readable medium” shallaccordingly be taken to include, but not be limited to, solid-statememories, optical mediums, and magnetic mediums.

The embodiments disclosed herein include various steps. The steps of theembodiments disclosed herein may be formed by hardware components or maybe embodied in machine-executable instructions, which may be used tocause a general-purpose or special-purpose processor programmed with theinstructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware and software.

The embodiments disclosed herein may be provided as a computer programproduct, or software, that may include a machine-readable medium (orcomputer-readable medium) having stored thereon instructions, which maybe used to program a computer system (or other electronic devices) toperform a process according to the embodiments disclosed herein. Amachine-readable medium includes any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer). For example, a machine-readable medium includes: amachine-readable storage medium (e.g., ROM, random access memory(“RAM”), a magnetic disk storage medium, an optical storage medium,flash memory devices, etc.), and the like.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is no way intended thatany particular order be inferred.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention. Since modifications combinations,sub-combinations and variations of the disclosed embodimentsincorporating the spirit and substance of the invention may occur topersons skilled in the art, the invention should be construed to includeeverything within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. A spectrum optimization unit in a distributedantenna system (DAS), comprising: a spectrum analysis unitcommunicatively coupled to a plurality of remote antenna unit (RAU)coverage areas in a DAS, the plurality of RAU coverage areas eachconfigured to communicate on a respective first radio frequency (RF)channel; the spectrum analysis unit configured to: receive a pluralityof sniffed RF signals from the plurality of RAU coverage areas,respectively, wherein each of the plurality of sniffed RF signalscomprises one or more RF signals sniffed by at least one RAU in arespective RAU coverage area; and for each of the plurality of sniffedRF signals: analyze the one or more RF signals comprised in theplurality of sniffed RF signals; and determine a respective second RFchannel for the respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel; and acontroller configured to reconfigure one or more RAU coverage areasamong the plurality of RAU coverage areas to communicate on one or morerespective second RF channels in response to the one or more respectivesecond RF channels being determined by the spectrum analysis unit,wherein: each of the plurality of sniffed RF signals comprises one ormore downlink RF signals sniffed by the at least one RAU on therespective first RF channel in the respective RAU coverage area; thespectrum analysis unit is further configured to identify a power-leakingRAU in an RAU coverage area among the plurality of RAU coverage areas,wherein the power-leaking RAU interferes with another RAU coverage areaamong the plurality of RAU coverage areas that is different from therespective RAU coverage area of the power-leaking RAU; and thecontroller is further configured to reduce RF power level of thepower-leaking RAU identified by the spectrum analysis unit.
 2. Thespectrum optimization unit of claim 1, wherein each of the plurality ofsniffed RF signals comprises one or more uplink RF signals sniffed bythe at least one RAU on the respective first RF channel in therespective RAU coverage area.
 3. The spectrum optimization unit of claim1, wherein each of the plurality of sniffed RF signals comprises one ormore configured RF signals sniffed by the at least one RAU on therespective first RF channel in the respective RAU coverage area.
 4. Thespectrum optimization unit of claim 1, wherein each of the plurality ofsniffed RF signals comprises one or more ad hoc RF signals sniffed bythe at least one RAU on the respective first RF channel in therespective RAU coverage area.
 5. The spectrum optimization unit of claim1, wherein the spectrum analysis unit is further configured to analyzethe one or more RF signals comprised in each of the plurality of sniffedRF signals to determine a downlink RF signal among the one or more RFsignals that is received from a cellular base station (BS).
 6. Thespectrum optimization unit of claim 1, wherein the spectrum analysisunit is further configured to analyze the one or more RF signalscomprised in each of the plurality of sniffed RF signals to determine adownlink RF signal among the one or more RF signals that is receivedfrom a mobile station (MS).
 7. A spectrum optimization unit in adistributed antenna system (DAS), comprising: a spectrum analysis unitcommunicatively coupled to a plurality of remote antenna unit (RAU)coverage areas in a DAS, the plurality of RAU coverage areas eachconfigured to communicate on a respective first radio frequency (RF)channel; the spectrum analysis unit configured to: receive a pluralityof sniffed RF signals from the plurality of RAU coverage areas,respectively, wherein each of the plurality of sniffed RF signalscomprises one or more RF signals sniffed by at least one RAU in arespective RAU coverage area; and for each of the plurality of sniffedRF signals: analyze the one or more RF signals comprised in theplurality of sniffed RF signals; and determine a respective second RFchannel for the respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel; and acontroller configured to reconfigure one or more RAU coverage areasamong the plurality of RAU coverage areas to communicate on one or morerespective second RF channels in response to the one or more respectivesecond RF channels being determined by the spectrum analysis unit asignal interface configured to: receive one or more downlinkcommunications signals from one or more communications signal sources,each of the one or more downlink communications signals is associatedwith a respective RF channel; receive a channel control signal from thecontroller, wherein the channel control signal identifies the one ormore RAU coverage areas to be reconfigured to operate on the one or morerespective second RF channels; and for each of the one or more RAUcoverage areas to be reconfigured to operate on the one or morerespective second RF channels: identify a downlink communications signalamong the one or more downlink communications signals received from theone or more communications signal sources, wherein the downlinkcommunications signal is associated with a respective RF channel thatmatches the respective second RF channel determined by the spectrumanalysis unit for the respective RAU coverage area; and route theidentified downlink communications signal for distribution to therespective RAU coverage area.
 8. A spectrum optimization unit in adistributed antenna system (DAS), comprising: a spectrum analysis unitcommunicatively coupled to a plurality of remote antenna unit (RAU)coverage areas in a DAS, the plurality of RAU coverage areas eachconfigured to communicate on a respective first radio frequency (RF)channel; the spectrum analysis unit configured to: receive a pluralityof sniffed RF signals from the plurality of RAU coverage areas,respectively, wherein each of the plurality of sniffed RF signalscomprises one or more RF signals sniffed by at least one RAU in arespective RAU coverage area; and for each of the plurality of sniffedRF signals: analyze the one or more RF signals comprised in theplurality of sniffed RF signals; and determine a respective second RFchannel for the respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel; and acontroller configured to reconfigure one or more RAU coverage areasamong the plurality of RAU coverage areas to communicate on one or morerespective second RF channels in response to the one or more respectivesecond RF channels being determined by the spectrum analysis unit,wherein: each of the plurality of sniffed RF signals comprises one ormore downlink RF signals sniffed by the at least one RAU on therespective first RF channel in the respective RAU coverage area; and thespectrum analysis unit is further configured to: identify an RAUcoverage area among the plurality of RAU coverage areas as an over-sizedRAU coverage area if the RAU coverage area has an expanded coverageboundary larger than a planned coverage boundary; and identify an RAUcoverage area among the plurality of RAU coverage areas as anunder-sized RAU coverage area if the RAU coverage area has a reducedcoverage boundary smaller than the planned coverage boundary; and thecontroller is further configured to reduce the expanded coverageboundary of the over-sized RAU coverage area by reducing RF power levelof one or more RAUs in the over-sized RAU coverage area.
 9. A spectrumoptimization unit in a distributed antenna system (DAS), comprising: aspectrum analysis unit communicatively coupled to a plurality of remoteantenna unit (RAU) coverage areas in a DAS, the plurality of RAUcoverage areas each configured to communicate on a respective firstradio frequency (RF) channel; the spectrum analysis unit configured to:receive a plurality of sniffed RF signals from the plurality of RAUcoverage areas, respectively, wherein each of the plurality of sniffedRF signals comprises one or more RF signals sniffed by at least one RAUin a respective RAU coverage area; and for each of the plurality ofsniffed RF signals: analyze the one or more RF signals comprised in theplurality of sniffed RF signals; and determine a respective second RFchannel for the respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel; and acontroller configured to reconfigure one or more RAU coverage areasamong the plurality of RAU coverage areas to communicate on one or morerespective second RF channels in response to the one or more respectivesecond RF channels being determined by the spectrum analysis unit,wherein: each of the plurality of sniffed RF signals comprises one ormore downlink RF signals sniffed by the at least one RAU on therespective first RF channel in the respective RAU coverage area; and thespectrum analysis unit is further configured to: identify an RAUcoverage area among the plurality of RAU coverage areas as an over-sizedRAU coverage area if the RAU coverage area has an expanded coverageboundary larger than a planned coverage boundary; and identify an RAUcoverage area among the plurality of RAU coverage areas as anunder-sized RAU coverage area if the RAU coverage area has a reducedcoverage boundary smaller than the planned coverage boundary; and thecontroller is further configured to increase the reduced coverageboundary of the under-sized RAU coverage area by increasing RF powerlevel of one or more RAUs in the under-sized RAU coverage area.
 10. Amethod for reducing radio frequency (RF) interferences in a plurality ofremote antenna unit (RAU) coverage areas in a distributed antenna system(DAS), comprising: receiving a plurality of sniffed RF signals from aplurality of RAU coverage areas, respectively, wherein each of theplurality of RAU coverage areas is configured to communicate on arespective first RF channel; for each of the plurality of sniffed RFsignals received from the plurality of RAU coverage areas: analyzing theplurality of sniffed RF signals to determine a respective second RFchannel for a respective RAU coverage area if the respective second RFchannel is lesser-interfered than the respective first RF channel of therespective RAU coverage area; and reconfiguring the respective RAUcoverage area to communicate on the respective second RF channel;identifying a power-leaking RAU in an RAU coverage area among theplurality of RAU coverage areas, wherein the power-leaking RAUinterferes with another RAU coverage area among the plurality of RAUcoverage areas that is different from the respective RAU coverage areaof the power-leaking RAU; reducing RF power level of the power-leakingRAU; identifying an RAU coverage area among the plurality of RAUcoverage areas as an over-sized RAU coverage area if the RAU coveragearea has an expanded coverage boundary larger than a planned coverageboundary; identifying an RAU coverage area among the plurality of RAUcoverage areas as an under-sized RAU coverage area if the RAU coveragearea has a reduced coverage boundary smaller than the planned coverageboundary; reducing the expanded coverage boundary of the over-sized RAUcoverage area by reducing RF power level of one or more RAUs in theover-sized RAU coverage area; and increasing the reduced coverageboundary of the under-sized RAU coverage area by increasing RF powerlevel of one or more RAUs in the under-sized RAU coverage area.
 11. Adistributed antenna system (DAS), comprising: a plurality of remoteantenna unit (RAU) coverage areas in a DAS, wherein each of theplurality of RAU coverage areas is configured to communicate on arespective first radio frequency (RF) channel; and a head-end equipment(HEE) coupled to the plurality of RAU coverage areas over a plurality ofcommunications mediums, respectively, the HEE comprising a spectrumoptimization unit; the spectrum optimization unit comprising: a spectrumanalysis unit configured to: receive a plurality of sniffed RF signalsfrom the plurality of RAU coverage areas, respectively, wherein each ofthe plurality of sniffed RF signals comprises one or more RF signalssniffed by at least one RAU in a respective RAU coverage area; and foreach of the plurality of sniffed RF signals:  analyze the one or more RFsignals comprised in the plurality of sniffed RF signals; and  determinea respective second RF channel for the respective RAU coverage area ifthe respective second RF channel is lesser-interfered than therespective first RF channel; and a controller configured to reconfigureone or more RAU coverage areas among the plurality of RAU coverage areasto communicate on one or more respective second RF channels in responseto the one or more respective second RF channels being determined by thespectrum analysis unit, wherein the spectrum optimization unit furthercomprises a signal interface configured to: receive one or more downlinkcommunications signals from one or more communications signal sources,each of the one or more downlink communications signals associated witha respective RF channel; receive a control signal from the controller,wherein the control signal identifies the one or more RAU coverage areasto be reconfigured to operate on the one or more respective second RFchannels; and for each of the one or more RAU coverage areas to bereconfigured to operate on the one or more respective second RFchannels: identify a downlink communications signal among the one ormore downlink communications signals received from the one or morecommunications signal sources, wherein a respective RF channel of thedownlink communications signal is the same as the respective second RFchannel of the respective RAU coverage area; and route the identifieddownlink communications signal to the respective RAU coverage area. 12.The DAS of claim 11, wherein each of the plurality of communicationsmediums comprises: a respective downlink data signal path forcommunicating the one or more downlink communications signals to theplurality of RAU coverage areas; and a respective uplink data signalpath for receiving one or more uplink communications signals from theplurality of RAU coverage areas.
 13. The DAS of claim 12, wherein the RFsignal router configured to: receive the one or more downlinkcommunications signals from the signal interface; and provide the one ormore downlink communications signals to the plurality of RAU coverageareas over the respective downlink data signal path in the plurality ofcommunications mediums.
 14. The DAS of claim 13, wherein the RF signalrouter is further configured to: receive the one or more uplinkcommunications signals and the plurality of sniffed RF signals from theplurality of RAU coverage areas over the respective uplink data signalpath in the plurality of communications mediums; provide the pluralityof sniffed RF signals to the spectrum analysis unit; and provide the oneor more uplink communications signals to the signal interface.
 15. TheDAS of claim 12, wherein: the spectrum analysis unit is furtherconfigured to identify a power-leaking RAU in an RAU coverage area amongthe plurality of RAU coverage areas, wherein the power-leaking RAUinterferes with another RAU coverage area among the plurality of RAUcoverage areas that is different from the respective RAU coverage areaof the power-leaking RAU; and the controller is further configured toreduce RF power level of the power-leaking RAU identified by thespectrum analysis unit.
 16. The DAS of claim 11, wherein the pluralityof communications mediums is a plurality of optical fiber-basedcommunications mediums, each of the plurality of optical fiber-basedcommunications mediums comprising: a respective downlink data signalpath for communicating the one or more downlink communications signalsto the plurality of RAU coverage areas; and a respective uplink datasignal path for receiving one or more uplink communications signals fromthe plurality of RAU coverage areas.
 17. The DAS of claim 16, wherein:the respective downlink data signal path is provided by a respectivedownlink data optical fiber; and the respective uplink data signal pathis provided by a respective uplink data optical fiber.
 18. The DAS ofclaim 16, wherein the HEE further comprises an RF signal routerconfigured to: receive the one or more downlink communications signalsfrom the signal interface; provide the one or more downlinkcommunications signals to at least one optical interface module (OIM) inthe HEE; receive the plurality of sniffed RF signals from the at leastone OIM; provide the plurality of sniffed RF signals to the spectrumanalysis unit; receive the one or more uplink communications signalsfrom the at least one OIM; and provide the one or more uplinkcommunications signals to the signal interface.
 19. The DAS of claim 18,wherein the at least one OIM is configured to: convert the one or moredownlink communications signals into a plurality of downlink opticalsignals; and provide the plurality of downlink optical signals to theplurality of RAU coverage areas over the respective downlink data signalpath in the plurality of optical fiber-based communications mediums. 20.The DAS of claim 18, wherein the at least one OIM is configured to:receive a plurality of optical sniffed RF signals from the plurality ofRAU coverage areas over the respective uplink data signal path in theplurality of optical fiber-based communications mediums, respectively;convert the plurality of optical sniffed RF signals into the pluralityof sniffed RF signals, respectively; provide the plurality of sniffed RFsignals to the spectrum analysis unit; receive a plurality of uplinkoptical signals from the plurality of RAU coverage areas over therespective uplink data signal path in the plurality of opticalfiber-based communications mediums; convert the plurality of uplinkoptical signals into the one or more uplink communications signals; andprovide the one or more uplink communications signals to the signalinterface.
 21. A distributed antenna system (DAS), comprising: aplurality of remote antenna unit (RAU) coverage areas in a DAS, whereineach of the plurality of RAU coverage areas is configured to communicateon a respective first radio frequency (RF) channel; and a head-endequipment (HEE) coupled to the plurality of RAU coverage areas over aplurality of communications mediums, respectively, the HEE comprising aspectrum optimization unit; the spectrum optimization unit comprising: aspectrum analysis unit configured to: receive a plurality of sniffed RFsignals from the plurality of RAU coverage areas, respectively, whereineach of the plurality of sniffed RF signals comprises one or more RFsignals sniffed by at least one RAU in a respective RAU coverage area;and for each of the plurality of sniffed RF signals:  analyze the one ormore RF signals comprised in the plurality of sniffed RF signals; and determine a respective second RF channel for the respective RAUcoverage area if the respective second RF channel is lesser-interferedthan the respective first RF channel; and a controller configured toreconfigure one or more RAU coverage areas among the plurality of RAUcoverage areas to communicate on one or more respective second RFchannels in response to the one or more respective second RF channelsbeing determined by the spectrum analysis unit, wherein: the spectrumanalysis unit is further configured to: identify an RAU coverage areaamong the plurality of RAU coverage areas as an over-sized RAU coveragearea if the RAU coverage area has an expanded coverage boundary largerthan a planned coverage boundary; and identify an RAU coverage areaamong the plurality of RAU coverage areas as an under-sized RAU coveragearea if the RAU coverage area has a reduced coverage boundary smallerthan the planned coverage boundary; and the controller is furtherconfigured to: reduce the expanded coverage boundary of the over-sizedRAU coverage area by reducing RF power level of one or more RAUs in theover-sized RAU coverage area; and increase the reduced coverage boundaryof the under-sized RAU coverage area by increasing RF power level of oneor more RAUs in the under-sized RAU coverage area.